The present invention relates to the field of aviation, and provides a solar-powered aircraft which is lighter than air at certain times, and heavier than air at other times.
A conventional, heavier-than-air aircraft requires a source of energy to stay aloft. The amount of time an aircraft can remain aloft is limited by the amount of fuel on-board.
A lighter-than-air aircraft carries a gaseous lifting medium, such as hydrogen or helium, to maintain buoyancy, as well as some fuel to power a propeller or other means for directing the aircraft along a desired flight path. The gaseous medium is eventually consumed, as it becomes necessary to vent the gas in order to descend. Moreover, the supply of fuel is also limited. Thus, a lighter-than-air aircraft still cannot remain aloft indefinitely.
The present invention provides a solar-powered aircraft which, in theory, can remain aloft indefinitely, subject only to small amounts of leakage as described below.
One important use for the aircraft of the present invention is as an unmanned aerial vehicle (UAV), which is employed for long-duration aerial surveillance. The aircraft of the present invention is preferably constructed with a configuration that has inherently small radar and infrared signatures. Thus, the aircraft of the present invention can remain aloft for indefinite periods, while conducting surveillance in various contexts.
The aircraft of the present invention is not limited to a particular configuration or field of use. The invention can be used to make virtually any kind of aircraft.